Approximately 100 diabetic patients representing both adult onset and juvenile onset diabetes mellitus are being examined over a three year period for evidence of corneal and other anterior segment pathology. Consistent corneal lesions described as punctate epithelial defects have been found in both groups of patients but predominately in female patients. Extensive clinical correlations have been studied which relate to: diminished corneal sensation; decreased tear production; bacterial flora of the conjunctiva; corneal thickness and endothelial cell density. In addition, laboratory studies thus far have examined basement membrane abnormalities seen with electron microscopy, unusual HLA antigen loci, and the identification of sorbitol and other carbohydrates in the corneal epithelium. The purpose of this study is to define corneal and anterior segment pathology which is related to diabetes and to determine which patients can be expected to show unusual tissue response to surgical stress. Special preoperative and postoperative measures, therefore, might be utilized to enhance visual prognosis for the diabetic patient undergoing intraocular surgical procedures.